HR: 09:30h
AN: A51B-05    [Abstracts]
TI: Potential Effects of Methane and Nitrous Oxide on the Recovery of Stratospheric Ozone
AU: Li, Y
EM: yueli2@atmos.uiuc.edu
AF: University of Illinois, 105 S. Gregory St., Urbana, IL 61801 United States
AU: * Wuebbles, D J
EM: wuebbles@atmos.uiuc.edu
AF: University of Illinois, 105 S. Gregory St., Urbana, IL 61801 United States
AB: Stratospheric ozone concentrations have been significantly reduced in recent decades as a result of human activities. The international agreement to protect stratospheric ozone, the Montreal Protocol, has effectively reduced the human-related emissions of halocarbons containing chlorine and bromine. Since the implementation of the international controls on ozone depleting chemicals, an important focus in studies of stratospheric ozone has been on the detection of a turnaround in the downward trend and determination of when a recovery will occur, where a recovery is defined as a return to levels of ozone in the 1970s before the existence of the Antarctica ozone "hole". If halocarbons remained the only relevant human-related factor affecting ozone, the ozone layer would be expected to recover by roughly 2040-2045. However, there are a number of other factors, including non-CO2 greenhouse gas emissions, affecting the future recovery of ozone. In this study, we considered a range of scenarios for future trace gases emissions developed by IPCC (2001) using the UIUC two-dimensional Chemical-Transport Model (UIUC 2D CTM). We found that the future recovery depended greatly on future emissions of two major greenhouse gases, methane (CH4) and nitrous oxide (N2O). Evaluation of the effects of scenarios developed by the IPCC (Intergovernmental Panel on Climate Change, 2001) for future emissions of methane, nitrous oxide, and other gases suggests that these gases could greatly affect ozone recovery, including the possibility of ozone not recovering in this century. In addition, under all cases, the ozone distribution is always greatly different than that in the pre-1980 atmosphere.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0340 Middle atmosphere--composition and chemistry
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly